Enzyme-containing detergent compositions

ABSTRACT

ALKALINE DETERGENT COMPOSITIONS CONTAINING AN ORGANIC DETERGENT AND AN ALKALINE BUILDER SALT IN A WEIGHT RATIO OF ABOUT 1:30 TO ABOUT 4:1 AND AN ENZYMATIC MIXTURE OF ABOUT 0.001 TO ABOUT 10% OF A BACILLUS SUBTILUS-DERIVED CARLSBERG SUBTILISIN, AN X-RAY MUTATED BACILLUS SUBSTILUSDERIVED SUBTILISIN OR MIXTURE THEREOF AND ABOUT 0.0003 TO ABOUT 3% OF AN A-AMYLASE, A WEIGHT RATIO 3:1 IS PROTEASE TO A-AMYLASE OF ABOUT 30:1 TO ABOUT 3:1 IS EMPLOYED TO PROVIDE DETERGENT COMPOSITIONS HAVING EXCELLENT CLEANING AND STAIN REMOVAL PROPERTIES.

United States Patent Oflice 3,790,482 Patented Feb. 5, 1974 3,790,482 ENZYME-CONTAINING DETERGENT COMPOSITIONS Jack D. Jones, Cincinnati, and Everett J. Collier, New

Burlington, Ohio, assignors to The Procter & Gamble Company, Cincinnati, Ohio N Drawing. Continuation of abandoned application Ser. No. 721,081, Apr. 12, 1968. This application June 9, 1971, Ser. No. 151,552

Int. Cl. Clld 1/14, 1/37, 7/42 US. Cl. 252-525 1 Claim ABSTRACT OF THE DISCLOSURE This is a continuation of application Ser. No. 721,081, filed, Apr. 12, 1968, now abandoned.

FIELD OF THE INVENTION This invention relates to alkaline detergent compositions suitable as heavy duty laundering or pre-soak formulations containing a combination of an alkaline protease and an a-amylase and especially adapted to the removal of soils and stains. These compositions are comprised of an organic detergent, an alkaline builder salt and a specific combination of soiland stain-removing enzymatic components.

THE PRIOR ART The use of enzymes in admixture with detergent compositions is known. See US. Pat. 1,882,279 issued Oct. 11, 1932 to Frelinghusen, for example. Similarly, British Pat. 814,772 issued June 10, 1959, to Rohm & Haas GmbH; East German Pat. 14,296 published Jan. 6, 1958 to Leidholdt; and Jaag. Seifen, Ole, Fette, Wachse 88, No. 24, pp. 789-793 (November 1962) disclose enzymatic detergents containing mixtures of enzymes, while US. Pat. 3,220,928 issued Nov. 30, 196-5 to Brenner describes the use of solutions of enzymatic mixtures in the cleaning of filter presses.

While the use of mixtures of enzymes, e.g., proteases and amylases has been known in the detergency formulating arts, none of the compositions heretofore prepared have been entirely satisfactory in the attainment of high levels of cleaning and whitening and in the removal of a wide spectrum of proteinaceous, starchy and fatty soils and stains. The attainment of detergent compositions capable of providing such properties has been hampered at least in part by the fact that the precise manner in which enzymatic catalysis occurs through interaction with soils and stains is not completely understood. The present invention by a combination of specific enzymatic materials exhibiting a surprising cooperative efiect provides for the formulation of superior levels of cleaning and whitening in the laundering of fabrics having a varied composition of soils and stains.

OBJECTS It is an object of the present invention to provide enzyme-containing detergent compositions exhibiting superior cleaning and whitening properties in the laundering of fabrics having a varied composition of soils and stains.

It is a further object of the present invention to provide enzyme-containing detergent compositions exhibiting superior cleaning and whitening properties in the laundering of fabrics having a combination of proteinaceous, starchy and fatty soils and stains.

Other objects of the invention will become apparent by consideration of the invention which is described more fully hereinafter.

SUMMARY OF THE INVENTION These and other objects of the present invention are attained by the provision of enzyme-containing detergent compositions which consist essentially of a mixture of an organic detergent and an alkaline builder salt in a ratio of alkaline builder salt to organic detergent of about 30:1 to about 1:4; about 0.001 to about 10% of an alkaline protease selected from the group consisting of (1) a Bacillus subzilus-derived Carlsberg subtilisin (2) an X-ray mutated Bacillus subtilus-derived subtilisin and (3) mixtures thereof; and

about 0.0003 to about 3% of an tat-amylase, in a weight ratio of alkaline protease to a-amylase of about 30:1 to about 3: 1. These compositions which have a pH in aqueous solution at a concentration of about 8.5 to about 11 and preferably about 9 to about 10.2 provide excellent cleaning and soiland stain-removal properties.

DETAILS AND DESCRIPTION OF THE INVENTION The enzyme-containing laundering and pre-soak compositions of the present invention are comprised of about 1% to about 50% organic detergent by weight of the total composition. Laundering compositions contain about 10 to about 50% of an organic detergent. The organic detergents suitable for use in the detergent compositions of the present invention include soap, anionic synthetic detergents, nonionic synthetic detergents, zwitterionic synthetic detergents and ampholytic synthetic detergents, and mixtures thereof.

Examples of suitable detergent compounds which can be employed in accordance with the present invention include the following:

(a) Water-soluble soaps: Examples of suitable soaps for use in this invention are the sodium, potassium, ammonium and alkanolammonium (e.g., mono-, di-, and triethanolammom'um) salts of higher fatty acids (C C Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium and potassium tallow and coconut soaps.

(b) Anionic synthetic non-soap detergents: A preferred class can be broadly descibed as the water-soluble salts, particularly the alkali metal salts, of organic, sulfuric acid reaction products having in their molecular structure an alkyl radical containing from about 8 to about 22 carbon atoms and a radical selected from the group consisting of sulfonic acid and sulfuric acid ester radicals. (Included in the term alkyl is the alkyl portion of higher acyl radicals.) Important examples of these anionic synthetic detergents are the sodium or potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (Cg-C 3 carbon atoms) produced by reducing the glycerides of tallow or coconut oil; sodium or potassium alkyl benzene sulfonates, in which the alkyl group can be a straight or branched chain and contains from about 9 to about 15 carbon atoms, preferably about 12-14 carbons; sodium alkyl glyceryl ether sulfonates,

especially those others of the higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfates and sulfonates; sodium or potassium salts of sulfuric acid esters of the reaction product of one mole of a higher fatty alcohol (e.g., tallow or coconut oil alcohols) and about 1 to 6 moles of ethylene oxide; sodium or potassium alkyl phenol ethylene oxide ether sulfates, with 1 to 10 units of ethylene oxide per molecule and wherein the alkyl radicals contain from 8 to 12 carbon atoms; the reaction product of fatty acids esterified with isethionic acid and neutralized with sodium hydroxide where, for example, the fatty acids are derived from coconut oil; sodium or potassium salts of fatty acid amide of a methyl tauride in which the fatty acids, for example, are derived from coconut oil; sodium and potassium salts of SO sulfonated C -C a olefins.

(c) Nonionic synthetic detergents: One class of nonionic detergents can be broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. A second class of nonionic detergents comprises higher fatty amides. A third class of nonionic detergents has semipolar characteristics. These three classes can be defined in further detail as follows:

(1) One class of nonionic synthetic detergents is marketed under the trade name of Pluronic. These detergent compounds are formed by condensing ethylene oxide with a hydropobic base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of the molecule which, of course, exhibits water insolubility, has a molecular weight of from about 1500 to 180 0. The addition of polyoxyethylene radicals to this hydrophobic portion tends to increase the water solubility of the molecule as a whole and the liquid character of the product is retained up to the point where the polyoxyethylene content is about 50% of the total weight of the condensation product.

(2) Alkylphenol-polyethylene oxide condensates are condensation products of alkyl phenols having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branched chain configuration with ethylene oxide, the said ethylene oxide being present in amounts equal to to 25 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived from polymerized propylene, diisobutylene, octene, or nonene, for example.

3) Nonionic synthetic detergents can be derived from the condensation of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine and include compounds containing from about 40% to about 80% polyoxyethylene by weight and having a molecular weight of from about 5,000 to about 11,000. Such compounds result from the reaction of ethylene oxide with a hydrophobic base constituted of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of the order of 2,500 to 3,000.

(4) Other nonionic detergents include condensation products of aliphatic alcohols having from 8 to 22 carbon atoms, in either straight chain or branched chain configuration, with ethylene oxide, e.g., a coconut alcoholethylene oxide condensate having from 5 to 30 moles of ethylene oxide per mole of coconut alcohol.

(5) The ammonia, monoethanol and diethanol amides of fatty acids having an acyl moiety of from about 8 to about 18 carbon atoms are useful nonionic detergents. These acyl moieties are normally derived from naturally occurring glycerides, e.g., coconut oil, palm oil, soybean oil and tallow, but can be derived synthetically, e.g., by

the oxidation of petroleum, or by hydrogenation of carbon monoxide by the Fischer-Tropsch process.

(6) Semi-polar nonionic detergents include long chain tertiary amine oxides corresponding to the following general formula wherein R is an alkyl radical of from about 8 to about 18 carbon atoms, R and R are each methyl, ethyl or hydroxyethyl radicals, R is ethylene, and n ranges from 0 to about 10. The arrow in the formula is a conventional representation of a semi-polar bond. Specific examples of amine oxide detergents include dimethyldodecylamine oxide and bis-(2-hydroxyethyl) dodecylamine oxide.

(7) Other semi-polar nonionic detergents include long chain tertiary phosphine oxides corresponding to the following general formula RRR"P- O wherein R is an alkyl, alkenyl or monohydroxyalkyl radical containing from 10 to 20 carbon atoms and R and R" are each alkyl or monohydroxyalkyl groups containing from 1 to 3 carbon atoms. The arrow in the formula is a conventional representation of a semi-polar bond. Examples of suitable phosphine oxides are found in US. Pat. 3,304,- 263 which issued February 14, 1967, and include: dimethyldodecylphosphine oxide and dimethyl-(Z-hydroxydodecyl) phosphine oxide.

('8) Still other semi-polar nonionio synthetic detergents include long chain sulfoxides having the formula wherein R is an alkyl radical containing from about 10 to about 28 carbon atoms, from 0 to about 5 ether linkages and from O to about 2 hydroxyl substituents, at least one moiety of R being an alkyl radical containing 0 ether linkages and containing from about 10 to about 18 carbon atoms, and wherein R is an alkyl radical containing from 1 to 3 carbon atoms and from one to two bydroxyl groups. Specific examples of these sulfoxides are: dodecyl methyl sulfoxide and 3-hydroxy tridecyl methyl sulfoxide.

(d) Ampholytic synthetic detergents can be broadly described as derivatives of aliphatic secondary and tertiary amines, in which the aliphatic radical can be straight chain or branched alkyls and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfo, sulfato, phosphate, or phosphono. Examples of compounds falling within this definition are sodium-3-dodecylaminopropionate and sodium-3-dodecylaminopropane sulfonate.

(e) Zwitterionic synthetic detergents can be broadly described as derivatives of aliphatic quaternary ammonium, phosphonium and sulfonium compounds, in which the aliphatic radical can be straight chain or branched alkyl, and wherein one of the aliphatic substituents contains from about 8 to 24 carbon atoms and one contains an anionic water solubilizing group, e.g., carhoxy, sulfo, sulfato, phosphato or phosphono. Examples of compounds falling Within this definition are 3-(N,N-dimethyl-N-hexadecylarnmonio) propane-l-sulfonate and 3-(N,N-dimethyl-N-hexadecylammonio) 2 hydroxy propane-l-sulfonate which are preferred for their cool Water detergency characteristics. @See, for example, Snoddy et al., Canadian Pat. 708,148.

Peferred organic detergents include sodium alkyl benzene sulfonate, sodium alkyl sulfate, and mixtures thereof wherein the alkyl group is of branched or straight chain configuration and contains about 10 to about 18 carbon atoms. Specific examples of preferred organic detergents include sodium decyl benzene sulfonate, sodium dodecyl benzene sulfonate, sodium tridecyl benzene sulfonate, sodium tetradecyl benzene sulfonate, sodium hexadecyl benzene sulfonate, sodium octadecyl sulfate and sodium tetradecyl sulfate.

These soap and non-soap anionic, nonionic, ampholytic and zwitterionic detergent compounds can be used singly or in combination. The above examples are merely illustrations of the numerous suitable detergents. Other organic detergent compounds can also be used.

The alkaline builder salts which can be employed in the detergent compositions of the present invention are employed in an amount to provide a weight ratio of alkaline builder salt to organic detergent of about 30:1 to 1:4, preferably about 9:1 to about 1:1. These builder salts can be inorganic or organic in nature and can be selected from a wide variety of known builder salts. Suitable alkaline, inorganic builder salts include the alkali metal carbonates, phosphates, polyphosphates and silicates. Specific examples of such salts are sodium and potassium tripolyphosphates, carbonates, phosphates and hexametaphosphates.

Suitable alkaline organic builder salts include the alkali metal, ammonium and substituted ammonium polyphosphonates, polyacetates, and polycarboxylates.

The polyphosphonates specifically include the sodium and potassium salts of ethylene diphosphonic acid, sodium and potassium salts of ethane-1-hydroxy-1,1-diphosphonic acid and sodium and potassium salts of ethane- 1,1,2-triphosphonic acid. Other examples include the water-soluble [sodium, potassium, ammonium and substituted ammonium (substituted ammonium, as used herein, includes mono, di-, and triethanol ammonium cations)] salts of ethane-Z-carboxy 1,1-diphosphonic acid, hydroxymethanediphosphonic acid, carbonyldiphosphonic acid, ethane-l-hydroxy-1,1,2-triphosphonic acid, ethane-Z-hydroxy-1,1,2-triphosphonic acid, propane-1,1,3,3-tetraphosphonic acid, propane-l,1,2,3-tetraphosphonic acid, and propane-l,2,2,3-tetraphosphonic acid.

Examples of the above polyphosphonic compounds are disclosed in US. Pats. 3,159,581 and 3,213,030 and US. patent applications, Ser. No. 266,055, filed Mar. 18, 1963; Ser. No. 368,419, now abandoned, filed May 18, 1964; Ser. No. 517,073, filed Dec. 28, 1965; Ser. No. 507,662, filed Nov. 15, 1965; and Ser. No. 489,687, filed Sept. 23, 1965.

The polyacetate builder salts suitable for use herein include the sodium, potassium, lithium, ammonium, and substituted ammonium salts of the following acids:

ethylenediaminetetraacetic acid, N-(2-hydroxyethyl)-ethylenediaminetriacetic acid, N-(Z-hydroxyethyl)-nitrilodiacetic acid, diethylenetriaminepentaacetic acid, 1,2-diaminocyclohexanetetraacetic acid and nitrilotriacetic acid.

The trisodium salts of the above acids are generally and preferably utilized herein.

The polycarboxylate builder salts suitable for use herein consist of water-soluble salts of polymeric aliphatic polycarboxylic acids selected from the group consisting of:

(a) water-soluble salts of homopolymers of aliphatic polycarboxylic acids having the following empirical formula:

wherein X, Y, and Z are each selected from the group consisting of hydrogen, methyl, carboxyl, and carboxymethyl, at least one of X, Y, and Z being selected from the group consisting of carboxyl and carboxymethyl,

6 provided that X and Y canbe carboxymethyl only when Z is selected from carboxyl and carboxymethyl, wherein only one of X, Y, and Z can be methyl, and wherein n is a whole integer having a value within a range, the lower limit of which is three and the upper limit of which is determined by the solubility characteristics in an aqueous system;

(b) water-soluble salts of copolymers of at least two of the monomeric species having the empirical formula described in (a), and

(c) water-soluble salts of copolymers of a member selected from the group of alkylenes and monocarboxylic acids with the aliphatic polycarboxylic compounds described in (a), said copolymers having the general for- 6 1- H R in) Y 11:]1:

wherein R is selected from the group consisting of hydrogen, methyl, carboxyl, carboxymethyl, and carboxyethyl; wherein only one R can be methyl; wherein m is at least 45 mole percent of the copolymer; wherein X, Y, and Z are each selected from the group consisting of hydrogen, methyl, carboxyl, and carboxymethyl; at least one of X, Y, and Z being selected from the group of carboxyl and carboxymethyl provided that X and Y can be carboxymethyl only when Z is selected from the group of carboxyl and carboxymethyl, wherein only one of X, Y, and Z can be methyl and wherein n is a whole integer within a range, the lower limit of which is three and the upper limit of which is determined primarily by the solubility characteristics in an aqueous system; said polyelectrolyte builder material having a minimum molecular weight of 350 calculated as the acid form and an equivalent weight of about 50 to about 80, calculated as the acid form (e.g., polymers of itaconic acid, aconitic acid; maleic acid; mesaconic acid; fumaric acid; methylene malonic acid; and citraconic acid and copolymers with themselves and other compatible monomers such as ethylene). These polycarboxylate builder salts are more specifically described in US. Pat. 3,308,067, issued Mar. 7, 1967, to Francis L. Diehl, entitled Polyelectrolyte Builders and Detergent Compositions."

Mixtures of the above-described alkaline builder salts can be utilized to advantage in this invention.

The enzymatic components of the detergent composition of the present invention are employed as mixtures of an alkaline protease and an a-amylase. While applicants do not wish to be bound by any particular theory or mechanism as to the precise manner in which these enzymatic components function to provide superior cleaning and stain-removing properties, it is believed that the alkaline proteases and a-amylases of the present invention operate in a cooperative manner as catalytic components in the degradation of proteinaceous, starchy and lipid soils and stains.

The proteolytic enzymes utilizable in accordance with the present invention are enzymatic materials belonging to the class of enzymes known in the art as alkaline proteases. Where used hereinafter in the specification and claims, alkaline proteases are those materials which exhibit their greatest proteolytic activity in enzymatic cleaning, e.g., degradation of protein soil, in aqueous solutions at pHs ranging from about 7.8 to about 12 and at temperatures ranging from about 50 F. to about F.

The alkaline proteases of the present invention which are utilizable with a-amylases to provide conjoint enzymatic cleaning and stain-removing properties are proteclytic enzymes derived from the bacterial organism Bacillus subtilus and are termed subtilisms. The subtilisms of the present invention which in combination with a-amylases provide the advantageous properties hereinbefore described including the Bacillus subtilus-derived Carlsberg strain of subtilisin and an X-ray mutated Bacillus swbtilusderived subtilisin. It is preferred from a product stability standpoint to employ a mixture of both the Carlsberg and X-ray mutated Bacillus subtilus-derived subtilisins with a-amylase. Inasmuch as the presence of the Carlsberg subtilisin provides stability to detergent compositions containing X-ray mutated Bacillus subtilus-derived subtilisin and a-amylase and thereby increases shelf life, the employment of a mixture of these proteases and a-amylase constitutes a preferred aspect of the present invention.

The amount of Carlsberg or X-ray mutated Bacillus sabtilus-derived enzyme employed in combination with an a-amylase to provide the detergent compositions of the present invention is not critical and is an amount of proteolytic enzyme capable of eifecting the degradation of the proteinaceous matter normally encountered in a home laundering situation under normal washing conditions, e.g. at temperatures of about 50 F. to 160 F. and at pHs of about 6.5 to 10.5. Normally, the Carlsberg substilisin, X-ray mutated Bacillus subtilus-derived subtilisin or mixture thereof is employed in an amount of about 0.001 to 10% of the enzyme-containing detergent composition. Best results in terms of overall cleaning eflicacy and stain-removing properties are attained when the proteolytic enzyme is employed in an amount of about 0.01 to about 5%. While the amount of subtilisin employed herein is not critical per se; the cooperative effect of subtilisin and a-amylase in overall cleaning and in soiland stain-removing properties is found when the ratio of subtilisin to a-amylase is about 30:1 to 3:1 on a weight basis.

The Carlsberg strain employed in accordance with the present invention is a known subtilisin strain, the amino acid sequence of which is described in Smith et al., The Complete Amino Acid Sequence of Two Types of Subtilisin, BPN and Carlsberg, I. of Biol. Chem., vol. 241, Dec. 25, 1966, at page 5974. This subtilisin strain is characterized by a tyrosine to tryptophan ratio of about 13 to l. The above reference including its description of the amino acid sequence of the Carlsberg subtilisin is hereby incorporated by reference.

The mutated subtilisin of the present invention can be obtained by mutation of a Bacillus subtilis organism. This mutation can be effected in accordance with U.S. Pat. 3,031,380 issued Apr. 24, 1962 to Mingawa et al. by irradiation with X-rays. Subsequent treatment in a con ventional manner can be employed to result in the preparation of an enzymatic composition, U.S. 3,031,380 describes a process whereby an enzymatic composition is produced by subjecting Bacillus subtilis to X-rays of an intensity corresponding substantially to 24-50 roentgens for an interval of at least half an hour, selecting from the colony thus subjected to X-rays a strain identified by cells having hairless, rough, jagged, spotted and dull white characteristics, separating said strain and placing the separated strain in a culture selected from the group consisting of wheat bran and corn meal, maintaining the culture for a period of at least 40 hours while aerating the culture substantially continuously, and drying the culture. The disclosure of U.S. Pat. 3,031,380 is hereby incorporated by reference.

The above described proteases can be utilized in a pure form in the preparation of enzymecontaining detergent compositions. Generally, however, powdered commercial enzyme compositions containing these enzymes are utilized herein. These comercial compositions contain about 2% to about 80% alkaline protease in combination with inert powdered vehicles which may comprise sodium or calcium sulfate as the remaining 20% to 98%. These commercially available compositions can in addition contain minor amounts of lipid and carbohydrate materials as well as neutral proteases. These neutral proteases presout do not influence the activity found between alkaline proteases and alpha-amylas-es inasmuch as their degradative effect on proteinaceous matter is not generally demonstrated under the alkaline conditions found in the home laundering process or in the presence of the alkaline builder salts employed herein.

The activity of the alkaline proteases of the present invention can be readily expressed in terms of activity units, e.g., casein assay activity units. In accordance with the casein assay method of determining proteolytic activity, 1 ml. of a 0.005% solution of the protease to be evaluated is allowed to digest by hydrolysis, 1 ml. of a 2% solution of casein substrate at a temperature of 37 C. for 10 minutes at a pH of 10.3. The reaction is stopped by the addition of trichloroacetic acid, the solution is filtered and the color of the filtrate containing the digested casein is developed employing Folin-Ciocalteu phenol reagent. The degree of enzymatic activity is determined by comparing the spectrophotometric response with that of solutions of varying concentrations of reagent grade tyrosine and detel-mining the amount of tyrosine produced. The proteolytic enzyme has one protease activity unit for each microgram of tyrosine produced during hydrolysis. The casein assay method of determining proteolytic activity is well known and a more detailed discussion is found in B. Hagihara et al., J. Bichem. (Tokyo), 45, 185 (1958) and M. Kunitz, J. Gen. Physiol., 291 (1947).

The activities of the alkaline proteases of the present invention vary depending largely upon the concentration of alkaline protease in the enzymatic composition, upon calcium ion concentration, upon substrate concentration, and upon pH. Pure samples of alkaline proteases of the present invention are highly active. For example, the Bacillus subtilus-derived Carlsberg subtilisin employed herein is characterized by a protease activity unit numher on a pure basis of about 7,500,000 units/ gram. Commercially available compositions wherein the alkaline protease is present in varying amounts with inert filler material vary in activity from about 100,000 to about 1,500,000 units/gram. Similarly, the mutated Bacillus subtilus-derived subtilisin employed herein is characterized by an activity of about 7,500,000 units/gram on a pure basis, while the commercial preparations vary in activity from about 100,000 to about 1,500,000 units/gram.

As described hereinbefore, the amount of alkaline protease employed herein in the enzyme-containing detergent compositions of the present invention is about 0.001 to about 10% of the composition on a pure enzyme basis. This amount corresponds to the incorporation into the detergent composition of about 75 to about 750,000 protease activity units/ gram of detergent composition. It will of course be appreciated that the amount of enzymatic composition required in the formulation of detergent compositions having a desired level of proteolytic activity varies with the activity level of the enzyme-containing composition employed.

When a source of alkaline protease and inert carrier is employed wherein the enzymatic alkaline protease is present in a minor amount, e.g., about 2% and, hence, the activity unit value is in the lower region of the operable range, the relative inactivity can be compensated for by employing a relatively large amount of the enzymatic composition. Similarly, formulations having higher amounts, e.g., alkaline protease can be employed in relatively smaller amounts. The precise amounts of such materials employed in the formualtion of enzyme-containing detergent compositions can be readily determined by methods known in the art so long as the amounts of alkaline protease and tit-amylase are employed in the hereinbefore specified ranges and the ratio of the alkaline protease and ol-amylase is within the hereinbefore specified range.

Specific examples of the alkaline proteases suitable for use herein which are sold on a commercial basis are Alcalase (6% subtilisin-Carlsberg strain), Novo Industri, A/S, Copenhagen, Denmark and Monsanto CRD Protease (DA-10) (about 25%; subtilisin), Monsanto Company, St. Louis, Mo.; Alcalase and CRD-Protease are more specifically described in copending United States patent application, McCarty, Stabilized Aqueous Enzyme Preparation, Ser. No. 683,196, filed Nov. 15, 1967, which description is hereby incorporated by reference.

The a-amylases of the present invention are well known materials and are particularly well suited for breaking down starch molecules as they attack the a 1,4-glycosidic linkages in starch. The remaining shorter chains are easily removed with water or aqueous solutions of detergents. The a-amylases can be obtained from a number of sources, such as animals, cereal grains and bacterial sources. a-Amylases from Bacillus subtilus-containing sources are preferred herein for reasons of ready availability, desirable rate of hydrolysis and resistance to detergent inactivation.

The activity values of the a-amylases of the present invention can be conveniently expressed in terms of the amylase assay method. In accordance with this method, a sample of amylase is allowed to catalyze the hydrolysis of the 1,4 a-glucosidic bonds of starch and glycogen for minutes at a temperature of 37 C. and a pH of 6.0. The reaction is terminated by the addition of 3,5- dinitrosalicylic acid, the color is developed and the amount of maltose determined by spectrophotometric response and comparison with solutions of analytical grade maltose hydrate. The amylase has one activity unit for each 0.4 mg. of maltose hydrate produced during hydrolysis. The amylase activity method is well known and is described with greater particularity in P. Bernfeld, Adv. in Enzymol. 12, 379 (1951).

As in the case of alkaline proteases, a-amylases vary in activity depending upon their concentration in the enzymatic composition, upon calcium ion concentration and upon pH. Pure a-amylase has an amylase activity of about 11,500,000 units per gram while commercially available preparations varying in content of tat-amylase are characterized by activities of about 50,000 to about 1,500,000 amylase activity units/ gram. As described hereinbefore, the enzyme-containing detergent compositions of the present invention are characterized by the presence of about 0.0003 to about 3% by weight of tat-amylase which corresponds to the incorporation of about 40 to 400,000 amylase activity units per gram of detergent composition. The a-amylase is also employed in an amount such that the ratio of alkaline protease to a-amylase ranges about 30:1 to about 3:1. The employment of such an amount of u-amylase corresponds to a ratio of case in activity units to amylase activity units of about 47:1 to about 4.7 :1.

Commercial a-amylase compositions can be utilized herein and these compositions include Wallerstein Bacterial a-Amylase, Lot No. 4546A, Wallerstein Company, Staten Island, N.Y.; a-Amylase, Miles Chemical Company, Elkart, Indiana; the a-amylase which is an integral part of Monsantos CRD Protease (DA-) (derived from Bacillus subtilus); and tit-amylase, Midwest Biochemical Company, Milwaukee, Wis. Mixtures of these materials can be employed to advantage in the exercise of the present invention.

The enzyme-containing detergent compositions of the present invention can be prepared by methods well known to those skilled in .the art. For example, the enzymatic mixtures of the present inveniton can be mechanically mixed into a formulated detergent composition in an amount to provide the advantageous cleaning and whitening properties of the compositions hereinbefore described. In order to preserve the activity of the enzymatic mixtures of the present invention can be and humid climatic conditions, it is preferred to prepare enzyme carrier granules containing a mixture of alkaline protease and a-amylase and admix these enzyme-contain- 10 ing granules with alkaline detergent granules prepared by methods known in the art.

Enzyme-containing detergent composition of the preferred type can conveniently be prepared by dry-mixing about to about 98% detergent granules with about 2% to about 20%, preferably about 2% to about 12% by weight of enzyme carrier granules.

These preferred compositions are comprised by weight of the granular detergent composition of:

(a) about 80% to about 98% of detergent granules having a pH in aqueous solution at a concentration of about 0.12% by Weight ranging from about 8.5

. to about 11 and comprising alkaline builder salts and organic detergents, the ratio of alkaline builder salts to organic detergents ranging from about 30:1 to about 1.4;

(b) about 2% to about 20% of enzyme carrier granules having a pH in saturated aqueous solution ranging from about 5.0 to about 10.5 and comprising, by Weight of the enzyme carrier granules:

(1) about 20% to about 80% of sodium tripolyphosphate and sodium pyrophosphate;

(2) about 5% to about 50% of anionic synthetic detergents of the sulfate or sulfonate type, preferably sodium alkyl benzene sulfonate, sodium alkyl sulfate, or mixtures thereof, wherein the alkyl group is of branched or straight chain configuration and contains from about 10 to about 18 carbon atoms;

(3) about 1.0% to about 7% water; and

(4) about 0.01 to about 50% of an alkaline protease selected from the group consisting of a Bacillus subtilus-derived Carlsberg subtilisin, an X-ray mutated Bacillus subtillus-derived subtilisin and mixtures thereof; and

(5) about 0.003 to about 15% of an a-amylase in a ratio of alkaline protease to a-amylase of about 30:1 to about 3:1.

The bulk of the preferred detergent compositions of this invention, i.e., from 80% to about 98%, is comprised of detergent granules having a pH in aqueous solution at a concentration of 0.12% by weight (ordinary washing concentration) of from about 8.5 to about 11. This pH range is known to be most effective in Washing applications, especially in ordinary laundry situations. These detergent granules are comprised of alkaline builder salts and organic detergents in a ratio of alkaline builder salts to organic detergents. of from about 30:1 to about 1:4, preferably from about 9:1 to about 1:1.

The detergent granules utilized herein are preferably formed by the well-known spray-drying process. However, agglomerated granules can be utilized herein.

To obtain optimum cleaning results, the pH of an aqueous solution containing 0.12% by Weight of the above-described detergent granules (ordinary washing concentrations) should range from about 8.5 to about 11.0, preferably from 9.0 to 10.2.

The remaining 2% to 20%, preferably from 2% to 12%, of the preferred granular detergent compositions of this invention is comprised of special enzyme carrier granules. These enzyme carrier granules have a pH in saturated aqueous solution ranging from about 5.0 to about 10.5.

The enzyme carrier granules utilized herein are especially formulated to have the Same size and density characteristics as the bulk of the detergent granules to inhibit segregation of the enzymes in the packaged detergent composition. Additionally, the components of these enzyme carrier granules are so selected as to prevent lowering the efficacy of the detergent granules and of the detergent composition as a whole. These enzyme carrier granules are also partially effective in controlling free moisture and the relative humidity in the packaged detergent composition.

These enzyme carrier granules can advantageously be prepared by different methods, e.g., spray-drying or co agglomeration. The most preferred method of obtaining granules containing the above components is spray-drying. In this method, sodium tripolyphosphate or mixtures of sodium tripolyphosphate and sodium pyrophosphate, the anionic synthetic organic detergent, e.g., sodium alkyl benzene sulfonate, sodium alkyl sulfate or mixtures thereof, and water are slurried and this slurry is then spraydried to a moisture content of from about 1.0% to about 7%, preferably from 1.5% to 4%. An aqueous slurry of alkaline protease and u-amylase is then prepared and this slurry is sprayed onto the enzyme carrier granules. The water in the enzyme-water slurry is bound as water of hydration to the enzyme carrier granules and the enzymes are attached to the enzyme carrier granules. No more than about 7% water should be present in the enzyme carrier granules of this invention after the enzyme-water spray-on.

Another method of preparing the enzyme carrier granules of this invention is by coagglomeration. In this procedure, the various detergent ingredients, i.e., sodium tripolyphosphate, the anionic synthetic organic detergent, and the enzymes are sprayed with water and formed into agglomerates in a cement mixer, pan agglomerator or the like. The agglomerates so formed, i.e., enzyme carrier granules, are approximately the same size and density as those utilized in the bulk of the detergent composition.

Phosphate builder salts selected from the group consisting of sodium tripolyphosphate and mixtures of sodium tripolyphosphate and sodium pyrophosphate are one of the major components of the enzyme carrier granules and are utilized herein in amounts ranging from about 20% to about 80% by weight of the enzyme carrier granules and preferably in amounts ranging from about 40% to about 65%. The preferred phosphate builder salt is sodium tripolyphosphate.

Mixtures of the sodium salts of tripolyphosphoric acid and pyrophosphoric acid, Whether formed by heat degradation of sodium tripolyphosphate or by mixing the two phosphate builder salts, can contain up to 100% sodium tripolyphosphate and not more than about 45% sodium pyrophosphate. Preferably, the amount of sodium pyrophosphate does not exceed about 25% and is usually present in heat-dried sodium tripolyphosphate in amounts in excess of about 5% Sodium tripolyphosphate is a valuable component of the enzyme carrier granules because it provides alkaline builder characteristics and bulk tothese granules. This salt is especially valuable herein because in its anhydrous or partially hydrated form it acts as a moisture sink or desiccant and thus controls, to some extent, free moisture in the packaged detergent composition. Therefore, it is preferred that the sodium tripolyphosphate be utilized herein in its anhydrous or partially hydrated form.

The organic detergent is utilized in the enzyme carrier granules to prevent undesirable product dustiness (a large portion of very fine particles). The organic detergents, as a secondary advantage, enhance the washing capabilities of the detergent composition as a whole.

The detergent compositions of the present invention also contain a minor amount of water, i.e., about 1 to 15% of the detergent composition. Water is utilized in amounts ranging from about 1% to about 7% in the enzyme-carrier granules in conjunction with the organic detergents to minimize dustiness. However, no more than about 7% Water should be utilized in these granules. If more than about 7% water is utilized in these enzyme carrier granules, the desiccant effect of the sodium tripolyphosphate is alleviated and the formation of highly alkaline micro-solutions in close proximity to the enzymes is encouraged. The combination of these two effects can cause severe degradation and/or deactivation of the enzymes in the packaged detergent composition. It is preferred that the enzyme carrier granules contain from about 1.5% to about 4% water by weight of the enzyme granules.

By utilizing enzyme carrier granules, the stability of mixtures of alkaline proteases and a-amylases in detergent compositions is enhanced and the optimum pH range in aqueous solution is not significantly altered. The enzyme carrier granules can. be dyed to give the detergent composition of this invention a distinctive appearance, i.e., speckled, if desired.

The detergent compositions of the present invention can also contain any of the usual detergent adjuvants, diluents, and additives. For example, perfumes, antitarnishing agents, inert salts such as sodium sulfate, antiredeposition agents, bacteriostatic agents, dyes, fluorescers, suds builders, suds depressors, and the like, can be utilized herein without detracting from the advantageous properties of this composition. The advantageous properties of the detergent compositions of the present invention can also be shown in detergents containing oxygen bleaches such as sodium per-borate.

EXAMPLES Example I Enzyme carrier granules were prepared by mixing the following ingredients into a detergent slurry.

Ingredient: Parts by weight Anionic organic detergent paste 1 36.17 Sodium tripolyphosphate 70.03 Water 28.22 Sodium sulfate 4.55

Total 138.97

The organic detergent paste contained in parts by weight: 5 .06 parts sodium tall-ow alkyl sulfate; 4.14 parts sodium l near alkyl. benzene sulfonate having an alkyl chain length distribution of 16% C11, 27% C12, 35% C13, and 22% C14; 6.16 parts sodium sulfate; and 20.81 parts water.

This slurry was mixed until it was homogeneous after which the slurry was spray-dried to a total moisture content of 3.88%. 93.39 parts of enzyme carrier granules were obtained.

When this slurry was spray-dried, a portion of the sodium tripolyphosphate was degraded. The final distri' bution of phosphate salts on the basis of the original sodium tripolyphosphate added was 75.5% sodium tripolyphosphate; 21.4% sodium pyrophosphate and 3.1% sodium orthophosphate. These phosphate salts were partially hydrated.

Two parts of a mixture of about 8% Carlsberg subtilisin and balance inerts (Alcalase); 1.33 parts of a mixture of about 8% X-ray mutated Bacillus subtilus-derived subtilisin, about 3% inc-amylase and balance inerts (Monsanto DA-lO); and 3.33 parts water were slurried together and sprayed onto the 93.39 parts of enzyme carrier granules obtained above. The water was bound as water of hydration by the sodium tripolyphosphate and the enzymes were attached to the enzyme carrier granules. The pH of these enzyme carrier granules in saturated aqueous solution was about 8.5. Ten parts of these enzyme carrier granules were mixed with parts of spray-dried detergent granules which had a pH of about 9.2 in aqueous solution at a concentration of 0.12% by weight and which comprised in parts by weight of the detergent granules.

Ingredient: Parts by weight A mixture of 55% sodium tallow alkyl sulfate and 45% sodium linear alkyl benzene sulfonate wherein the alkyl chain distribution is 16% C Water 10.0

This detergent contains about 0.010% alkaline protease and a-amylase, the protease being a 2:1 ratio mixture of Carlsberg and X-ray mutated subtilisin. This detergent composition is an elfective cleaning and stain removing composition for most textile materials.

Example 11 The following ingredients are dry-mixed:

Ingredient: Parts by weight Sodium alkyl benzene'sulfonate derived from tetrapropylene 10.00 Sodium tripolyphosphate 70.00 Sodium sulfate 20.00 Bacillus subtz'lus-derived Carlsberg subtilisin 3.33 Bacillus subtilus-derived a-amylase 0.67

Total 104.00

673 parts water are sprayed onto this mixture and the ingredients are coagglomerated on a pan agglomerator into enzyme carrier granules having a pH in saturated aqueous solution of about 8.5.

Ten parts of these enzyme carrier granules are drymixed with 90 parts of the detergent granules of Example I. This composition combines excellent cleaning and stain-removing properties.

Example III The following ingredients are dry-mixed:

3.73 parts water are sprayed onto this mixture and the ingredients are coagglomerated on a pan agglomerator into enzyme carrier granules having a pH in saturated aqueous solution of about 8.5.

Ten parts of these enzyme carrier granules are drymixed with 90 parts of the detergent granules of Example I. This composition provides excellent whitening levels over a broad spectrum of soils and stains.

Example IV Results substantially similar to those obtained in the previous examples are obtained when the following builder salts are substituted, either wholly or in part, for sodlum tripolyphosphate in that the composition is an effective laundry detergent: sodium, potassium, ammonium, monoethanol ammonium, diethanol ammonium and triethanol ammonium salts of the following acids:

ethylenediainetetraacetic acid; N-(Z-hydroxyethyl)-ethylenediaminetriacetic acid; N-(Z-hydroxyethyl -nitrilodiacetic acid; diethylenetriaminepentaacetic acid;

nitrilotriacetic acid; ethylene diphosphonic acid; ethane-l-hydroxy-1,1-diphosphonic acid; ethane-1,1,2-triphosphonic acid; ethane-Z-carboxy-1,1-diphosphonic acid; hydroxymethane-diphosphonic acid; carbonyl-diphosphonic acid; ethane-l-hydroxy-l,1,2-triphosphonic acid; ethane-Z-hydroxy-l,1,2-triphosphonic acid; propane-1,1,3,3-tetraphosphonic acid; propane-1,1,2,3-tetraphosphonic acid; and propane-1,2,2,3-tetraphosphonic acid and potassium tripolyphosphate;

and salts of polymers of itaconic acid, aconitic acid, maleic acid, mesaconic acid, fumaric acid, methylene malonic acid and citraconic acid and copolymers with themselves and/or ethylene and/or acrylic acid in, eg, 1:1 molar ratios and having molecular weights of 75,000; 100,000; and 125,000 (the copolymers with ethylene and/ or acrylic acid having equivalent weights, based on the acid form of 65, 70 and 75); in the form of their sodium, potassium, triethanolam'monium, diethanolammonium and monoethanolammonium salts.

Results substantially similar to those obtained in the previous examples are obtained when the following organic detergents are substituted, either wholly or in part, for the sodium alkyl benzene sulfonate or mixtures of sodium alkyl benzene sulfonate and sodium tallow alkyl sulfate in that the composition is an effective laundry detergent: sodium linear dodecyl benzene sulfonate, the condensation product of 1 mole of dodecyl phenol with 15 moles of ethylene oxide, dimethyldodecylamine oxide, dimethyldodecylphosphine oxide, 3 (N,N-dimethyl-N- hexadecylammonio)-2-hydroxypropane 1 sulfonate and sodium-3-dodecylaminopropane sulfonate.

Results substantially similar to those obtained in the previous examples are obtained when the following anionic synthetic detergents are substituted, either wholly or in part, for the anionic synthetic detergents utilized in the enzyme carrier granules in that the enzyme carrier granules are not dusty and are of proper size and density: sodium decylbenzene sulfonate, sodium dodecylbenzene sulfonate, sodium tridecylbenzene sulfonate, sodium hexadecyl-benzene sulfonate, sodium octadecylbenzene sulfonate, sodium octadecyl sulfate, sodium hexadecyl sulfate, sodium tetradecyl sulfate, and sodium dodecyl sulfate, sodium tetradecene sulfonate, sodium dodecyl glyceryl ether sulfonate, sodium salts of the sulfated reaction product of 1 mole of coconut fatty alcohol and 3 moles of ethylene oxide.

Example V The following ingredients are dry-mixed:

Ingredient: Parts by weight Spray-dried detergent granules of Example I 94 X-ray mutated Bacillus subtilus-derived subtilisin 3 This composition combines effective cleaning and stainremovmg properties.

The enzyme-containing detergent compositions of the present invention when employed in a conventional man-. ner in the home laundering process are effective in the attainment of high levels of cleaning and soiland stainremoval over a broad spectrum of soils and stains. The precise manner in which the specific proteolytic enzymes of the present invention function in specific proportions with a-amylases to provide such high levels of stainand soil-removal qualities is not entirely understood. It has been found, however, that When a Bacillus subtilus-derived subtilisin of the hereinbefore described type or mixture thereof is combined in a specific range of proportions with an a-amylase, a surprising cooperative effect is demonstrated. An amount of a combination of both a proteolytic enzyme and an tit-amylase effects a whitening which is greater than that attainable by the use of the same amount of either enzyme alone.

The stain removing properties of combinations of pro teolytic enzymes and u-amylases of the present invention were evaluated in the following manner:

Muslin swatches. were stained by passing strips of muslin through a padding bath containing the staining solution, passing the muslin through a standard 2-roll wringer and hanging the strip to dry. Darker, more even staining was obtained by passing each strip through the staining bath to effect a second application followed by drying overnight at 120 F. The stained strip was cut into 5" x 5%" swatches and laundered in an automatic miniature washer at 125 F. in water of 7 grain hardness and for 10 minutes. The laundering treatment was conducted by washing in a solution of the test detergent composition 3 swatches each of (1) gravy-, (2) spinach-, and (3) milk substitute-stained muslin in the presence of two untreated terry-cloth swatches added to provide bulk to the washload.

The test composition was a conventional built anioniccontaining detergent formulation and was employed in an amount of 6.75 grams/1V2 gal. water (equivalent to 1 cup/l7 gal. water). The enzymatic composition to be evaluated was added in the form of a fresh solution in water to provide the desired testing level of enzymatic component. The swatches upon completion of the laundering were dried and ironed and their whiteness levels were measured in a conventional manner employing a Hunter Color Difference Meter. The model employed was Model D25 from Hunter Associates Laboratory, Fairfax, Va. This device operates on the principle of reflectance and measures degree of whiteness. The greater the Hunter value the greater the whiteness level. The effect of the presence of enzymatic components in the control detergent solution was determined by comparing the Hunter Whiteness value resulting therefrom with that resulting from non-enzymatic cleaning under the same conditions, i.e., the Hunter Whiteness value resulting from the use of the control detergent. The control detergent was comprised of Iugredigrt: Parts by weight A mixture of 55% sodium tallow alkyl sulfate and 45% sodium linear alkyl benzene sulfonate wherein the alkyl chain distribution is C11, C12, C13 and Results of the foregoing tests are tabulated in Table I.

The enzyme-containing detergent compositions of the present invention provide excellent cleaning, soiland stain-removing properties in the laundering of textile materials bearing soils and stains encountered under normal soiling conditions. The enzymatic components of the present compositions greatly assist in the removal of the following typical stains: spinach; grass; strawberries; cherries; steak sauce; chili sauce; spaghetti sauce; egg yolk; blood; baby formula (milk); tomato juice; ketchup; potted meat; gravy; cocoa. milk; cooked vegetables; creamed corn; wine; grape juice; and licorice.

The overall cleaning properties of the enzyme-contain ing compositions of the present invention were evaluated by conducting a wash-wear test described below employing a standardized control detergent composition and an enzyme-containing detergent composition of the present invention.

The wash-wear test was conducted in the following manner. White dress shirts, cotton T-shirts and other fabrics were distributed among various individuals. Each dress shirt and T-shirt was worn for one normal working day under uniform conditions and the other fabrics were used for their intended purposes. The soiled clothes and fabrics along with clean wash-cloth size swatches of terrycloth and muslin were then washed in a conventional automatic agitating-type washer having a water volume of 17 gallons for a 10 minute period with the control and the enzyme-containing detergent compositions. The wash water had an average hardness of 7 grains per gallon. The control detergent composition, described hereinbefore, was employed in an amount of 0.12% by weight. The enzyme-containing composition of the present invention was a composition corresponding to Example I except that it contained a ratio of Carlsberg to X-ray mutated subtilisin of 25:1. The fabrics after washing were rinsed, dried and graded.

Direct comparisons were made by panels of experts between pairs of shirts and fabrics worn and soiled by the same individual. The dress shirts, T-shirts and other fabrics were graded for degree of cleaning and whiteness. For purposes of this invention, the term cleaning is intended as referring to the ability of a built laundering detergent to remove deeply embedded soils and deposits such as occur in the collars and culfs of white shirts. Whiteness is intended as referring to the overall whiteness impression of areas which are only slightly or moderately soiled as, for example, the expansive portions of white dress shirts.

The combined data from the visual judgments were converted and were expressed on a scale ranging from zero to ten where zero represents the cleaning or whitening level obtained by washing with water alone and a value of ten represents the cleaning level of an excellent standardized detergent composition under optimum conditions. For purposes of this evaluation, a value grade of five on this scale represents a level of cleaning that is considered satisfactory in household practice. Table II below describes the results of the wash-wear evaluation.

I Carlsberg subtillsin.

2:1 mixture at Carlsberg and X-ray mutated Bacilluskubtilua-derivedfsubtilisin.

TABLE II Cleaning whiteness Control Having described the invention with particularity, what is claimed is:

1. An enzyme-containing granular laundry detergent composition consisting essentially of by weight of the granular detergent composition:

(a) about 17.5% of a mixture of 55% sodium tallow alkyl sulfate and 45% sodium linear alkyl benzene sulfonate wherein the alkyl chain distribution is 16% C11, C13 C13, and C14;

(b) about 50.0% sodium tripolyphosphate (c) about 6.0% sodium silicate having an SiO :Na O

ratio of 1.8:1

(d) about 2.5% coconut fatty acid ammonio amide (e) about 14.0% sodium sulfate (f) about 10.0% water, and

(g) about .0l% of an enzyme ingredient which consists essentially of about .0082% of an alkaline protease component which is a 2:1 mixture, on a weight basis, of a Bacillus subtilus-derived Carlsberg subtilisin and X-ray mutated Bacillus subtilus-derived subtilisin, and

about .0018% of an a-amylase which is a Baczlllus subtilus-derived a-amylase,

the ratio by weight of said alkaline protease component to said a-amylase being about 4.5: 1.

1 8 References Cited UNITED STATES PATENTS 3,451,935 6/1969 [Roald et al 252-435 3,558,498 1/1971 Eymery et al 552- 3,630,930 12/1971 Davis et a1. 252531 FOREIGN PATENTS 14,296 1/ 1958 East Germany. 814,772 6/1959 Great Britain.

OTHER REFERENCES Maxatasez Publication, Royal Netherlands Fermentation Ind. 'Ltd, Delft-Holland, April 1967 (copy in 252- Dig. 12) pp. 13 and 14.

Hoogerheide et al.; The Development of Biological Cleaning Compds., Kemian Teollisuus, No. 3, 1967, pp. 212-221.

Jaag, E.: Effect of Enzymatic Detergents, Seifen- Ole-Fette, Nasche, 88, No. 24, pp. 78979'1, November 1962.

Communication to Patent Oflice establishing date on which Maxatase Bulletin was available to public.

LEON D. ROSDAL, Primary Examiner P. E. WILLS, Assistant Examiner US. Cl. XJR. 252531, 534, 539 

